While urban mobile communications can be economically served by a trunk dispatch mobile network, a similar need for mobile communication in rural areas has not been satisfied. Urban land mobile systems operating in the 850 MHz band normally do not cover an area of more than about 30 miles in diameter. In order to cover the conventional United States, an excessively large number of such stations would be required, which would have to be interconnected to permit communication between mobile units in various areas. The relatively great dispersion of rural mobile units makes such a system uneconomical. A geostationary satellite communication system could be utilized to connect moderate numbers of widely dispersed mobile units, but to be acceptable such a system must occupy only a relatively small portion of the available high frequency spectrum, in spite of the need for communication with perhaps tens of thousands of different units dispersed over a wide area such as the continental United States.